UefiCpuPkg/Library/MpInitLib/DxeMpLib.c

   1 /** @file
   2   MP initialize support functions for DXE phase.
   3
   4   Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>
   5   This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 #include "MpLib.h"
  16
  17 #include <Library/UefiLib.h>
  18 #include <Library/UefiBootServicesTableLib.h>
  19
  20 #define  AP_CHECK_INTERVAL     (EFI_TIMER_PERIOD_MILLISECONDS (100))
  21 #define  AP_SAFE_STACK_SIZE    128
  22
  23 CPU_MP_DATA      *mCpuMpData = NULL;
  24 EFI_EVENT        mCheckAllApsEvent = NULL;
  25 EFI_EVENT        mMpInitExitBootServicesEvent = NULL;
  26 EFI_EVENT        mLegacyBootEvent = NULL;
  27 volatile BOOLEAN mStopCheckAllApsStatus = TRUE;
  28 VOID             *mReservedApLoopFunc = NULL;
  29 UINTN            mReservedTopOfApStack;
  30 volatile UINT32  mNumberToFinish = 0;
  31
  32 /**
  33   Get the pointer to CPU MP Data structure.
  34
  35   @return  The pointer to CPU MP Data structure.
  36 **/
  37 CPU_MP_DATA *
  38 GetCpuMpData (
  39   VOID
  40   )
  41 {
  42   ASSERT (mCpuMpData != NULL);
  43   return mCpuMpData;
  44 }
  45
  46 /**
  47   Save the pointer to CPU MP Data structure.
  48
  49   @param[in] CpuMpData  The pointer to CPU MP Data structure will be saved.
  50 **/
  51 VOID
  52 SaveCpuMpData (
  53   IN CPU_MP_DATA   *CpuMpData
  54   )
  55 {
  56   mCpuMpData = CpuMpData;
  57 }
  58
  59 /**
  60   Allocate reset vector buffer.
  61
  62   @param[in, out]  CpuMpData  The pointer to CPU MP Data structure.
  63 **/
  64 VOID
  65 AllocateResetVector (
  66   IN OUT CPU_MP_DATA          *CpuMpData
  67   )
  68 {
  69   EFI_STATUS            Status;
  70   UINTN                 ApResetVectorSize;
  71   EFI_PHYSICAL_ADDRESS  StartAddress;
  72
  73   if (CpuMpData->SaveRestoreFlag) {
  74     BackupAndPrepareWakeupBuffer (CpuMpData);
  75   } else {
  76     ApResetVectorSize = CpuMpData->AddressMap.RendezvousFunnelSize +
  77                         sizeof (MP_CPU_EXCHANGE_INFO);
  78
  79     StartAddress = BASE_1MB;
  80     Status = gBS->AllocatePages (
  81                     AllocateMaxAddress,
  82                     EfiACPIMemoryNVS,
  83                     EFI_SIZE_TO_PAGES (ApResetVectorSize),
  84                     &StartAddress
  85                     );
  86     ASSERT_EFI_ERROR (Status);
  87
  88     CpuMpData->WakeupBuffer      = (UINTN) StartAddress;
  89     CpuMpData->MpCpuExchangeInfo = (MP_CPU_EXCHANGE_INFO *) (UINTN)
  90                   (CpuMpData->WakeupBuffer + CpuMpData->AddressMap.RendezvousFunnelSize);
  91     //
  92     // copy AP reset code in it
  93     //
  94     CopyMem (
  95       (VOID *) CpuMpData->WakeupBuffer,
  96       (VOID *) CpuMpData->AddressMap.RendezvousFunnelAddress,
  97       CpuMpData->AddressMap.RendezvousFunnelSize
  98       );
  99   }
 100 }
 101
 102 /**
 103   Free AP reset vector buffer.
 104
 105   @param[in]  CpuMpData  The pointer to CPU MP Data structure.
 106 **/
 107 VOID
 108 FreeResetVector (
 109   IN CPU_MP_DATA              *CpuMpData
 110   )
 111 {
 112   EFI_STATUS            Status;
 113   UINTN                 ApResetVectorSize;
 114
 115   if (CpuMpData->SaveRestoreFlag) {
 116     RestoreWakeupBuffer (CpuMpData);
 117   } else {
 118     ApResetVectorSize = CpuMpData->AddressMap.RendezvousFunnelSize +
 119                         sizeof (MP_CPU_EXCHANGE_INFO);
 120     Status = gBS->FreePages(
 121                (EFI_PHYSICAL_ADDRESS)CpuMpData->WakeupBuffer,
 122                EFI_SIZE_TO_PAGES (ApResetVectorSize)
 123                );
 124     ASSERT_EFI_ERROR (Status);
 125   }
 126 }
 127
 128 /**
 129   Checks APs status and updates APs status if needed.
 130
 131 **/
 132 VOID
 133 CheckAndUpdateApsStatus (
 134   VOID
 135   )
 136 {
 137   UINTN                   ProcessorNumber;
 138   EFI_STATUS              Status;
 139   CPU_MP_DATA             *CpuMpData;
 140
 141   CpuMpData = GetCpuMpData ();
 142
 143   //
 144   // First, check whether pending StartupAllAPs() exists.
 145   //
 146   if (CpuMpData->WaitEvent != NULL) {
 147
 148     Status = CheckAllAPs ();
 149     //
 150     // If all APs finish for StartupAllAPs(), signal the WaitEvent for it.
 151     //
 152     if (Status != EFI_NOT_READY) {
 153       Status = gBS->SignalEvent (CpuMpData->WaitEvent);
 154       CpuMpData->WaitEvent = NULL;
 155     }
 156   }
 157
 158   //
 159   // Second, check whether pending StartupThisAPs() callings exist.
 160   //
 161   for (ProcessorNumber = 0; ProcessorNumber < CpuMpData->CpuCount; ProcessorNumber++) {
 162
 163     if (CpuMpData->CpuData[ProcessorNumber].WaitEvent == NULL) {
 164       continue;
 165     }
 166
 167     Status = CheckThisAP (ProcessorNumber);
 168
 169     if (Status != EFI_NOT_READY) {
 170       gBS->SignalEvent (CpuMpData->CpuData[ProcessorNumber].WaitEvent);
 171      CpuMpData->CpuData[ProcessorNumber].WaitEvent = NULL;
 172     }
 173   }
 174 }
 175
 176 /**
 177   Checks APs' status periodically.
 178
 179   This function is triggered by timer periodically to check the
 180   state of APs for StartupAllAPs() and StartupThisAP() executed
 181   in non-blocking mode.
 182
 183   @param[in]  Event    Event triggered.
 184   @param[in]  Context  Parameter passed with the event.
 185
 186 **/
 187 VOID
 188 EFIAPI
 189 CheckApsStatus (
 190   IN  EFI_EVENT                           Event,
 191   IN  VOID                                *Context
 192   )
 193 {
 194   //
 195   // If CheckApsStatus() is not stopped, otherwise return immediately.
 196   //
 197   if (!mStopCheckAllApsStatus) {
 198     CheckAndUpdateApsStatus ();
 199   }
 200 }
 201
 202 /**
 203   Get Protected mode code segment from current GDT table.
 204
 205   @return  Protected mode code segment value.
 206 **/
 207 UINT16
 208 GetProtectedModeCS (
 209   VOID
 210   )
 211 {
 212   IA32_DESCRIPTOR          GdtrDesc;
 213   IA32_SEGMENT_DESCRIPTOR  *GdtEntry;
 214   UINTN                    GdtEntryCount;
 215   UINT16                   Index;
 216
 217   Index = (UINT16) -1;
 218   AsmReadGdtr (&GdtrDesc);
 219   GdtEntryCount = (GdtrDesc.Limit + 1) / sizeof (IA32_SEGMENT_DESCRIPTOR);
 220   GdtEntry = (IA32_SEGMENT_DESCRIPTOR *) GdtrDesc.Base;
 221   for (Index = 0; Index < GdtEntryCount; Index++) {
 222     if (GdtEntry->Bits.L == 0) {
 223       if (GdtEntry->Bits.Type > 8 && GdtEntry->Bits.L == 0) {
 224         break;
 225       }
 226     }
 227     GdtEntry++;
 228   }
 229   ASSERT (Index != -1);
 230   return Index * 8;
 231 }
 232
 233 /**
 234   Do sync on APs.
 235
 236   @param[in, out] Buffer  Pointer to private data buffer.
 237 **/
 238 VOID
 239 EFIAPI
 240 RelocateApLoop (
 241   IN OUT VOID  *Buffer
 242   )
 243 {
 244   CPU_MP_DATA            *CpuMpData;
 245   BOOLEAN                MwaitSupport;
 246   ASM_RELOCATE_AP_LOOP   AsmRelocateApLoopFunc;
 247   UINTN                  ProcessorNumber;
 248
 249   MpInitLibWhoAmI (&ProcessorNumber);
 250   CpuMpData    = GetCpuMpData ();
 251   MwaitSupport = IsMwaitSupport ();
 252   AsmRelocateApLoopFunc = (ASM_RELOCATE_AP_LOOP) (UINTN) mReservedApLoopFunc;
 253   AsmRelocateApLoopFunc (
 254     MwaitSupport,
 255     CpuMpData->ApTargetCState,
 256     CpuMpData->PmCodeSegment,
 257     mReservedTopOfApStack - ProcessorNumber * AP_SAFE_STACK_SIZE,
 258     (UINTN) &mNumberToFinish
 259     );
 260   //
 261   // It should never reach here
 262   //
 263   ASSERT (FALSE);
 264 }
 265
 266 /**
 267   Callback function for ExitBootServices.
 268
 269   @param[in]  Event             Event whose notification function is being invoked.
 270   @param[in]  Context           The pointer to the notification function's context,
 271                                 which is implementation-dependent.
 272
 273 **/
 274 VOID
 275 EFIAPI
 276 MpInitChangeApLoopCallback (
 277   IN EFI_EVENT                Event,
 278   IN VOID                     *Context
 279   )
 280 {
 281   CPU_MP_DATA               *CpuMpData;
 282
 283   CpuMpData = GetCpuMpData ();
 284   CpuMpData->SaveRestoreFlag = TRUE;
 285   CpuMpData->PmCodeSegment = GetProtectedModeCS ();
 286   CpuMpData->ApLoopMode = PcdGet8 (PcdCpuApLoopMode);
 287   mNumberToFinish = CpuMpData->CpuCount - 1;
 288   WakeUpAP (CpuMpData, TRUE, 0, RelocateApLoop, NULL);
 289   while (mNumberToFinish > 0) {
 290     CpuPause ();
 291   }
 292   DEBUG ((DEBUG_INFO, "%a() done!\n", __FUNCTION__));
 293 }
 294
 295 /**
 296   Initialize global data for MP support.
 297
 298   @param[in] CpuMpData  The pointer to CPU MP Data structure.
 299 **/
 300 VOID
 301 InitMpGlobalData (
 302   IN CPU_MP_DATA               *CpuMpData
 303   )
 304 {
 305   EFI_STATUS                 Status;
 306   EFI_PHYSICAL_ADDRESS       Address;
 307   UINTN                      ApSafeBufferSize;
 308
 309   SaveCpuMpData (CpuMpData);
 310
 311   if (CpuMpData->CpuCount == 1) {
 312     //
 313     // If only BSP exists, return
 314     //
 315     return;
 316   }
 317
 318   //
 319   // Avoid APs access invalid buffer data which allocated by BootServices,
 320   // so we will allocate reserved data for AP loop code. We also need to
 321   // allocate this buffer below 4GB due to APs may be transferred to 32bit
 322   // protected mode on long mode DXE.
 323   // Allocating it in advance since memory services are not available in
 324   // Exit Boot Services callback function.
 325   //
 326   ApSafeBufferSize  = CpuMpData->AddressMap.RelocateApLoopFuncSize;
 327   ApSafeBufferSize += CpuMpData->CpuCount * AP_SAFE_STACK_SIZE;
 328
 329   Address = BASE_4GB - 1;
 330   Status  = gBS->AllocatePages (
 331                    AllocateMaxAddress,
 332                    EfiReservedMemoryType,
 333                    EFI_SIZE_TO_PAGES (ApSafeBufferSize),
 334                    &Address
 335                    );
 336   ASSERT_EFI_ERROR (Status);
 337   mReservedApLoopFunc = (VOID *) (UINTN) Address;
 338   ASSERT (mReservedApLoopFunc != NULL);
 339   mReservedTopOfApStack = (UINTN) Address + EFI_PAGES_TO_SIZE (EFI_SIZE_TO_PAGES (ApSafeBufferSize));
 340   ASSERT ((mReservedTopOfApStack & (UINTN)(CPU_STACK_ALIGNMENT - 1)) == 0);
 341   CopyMem (
 342     mReservedApLoopFunc,
 343     CpuMpData->AddressMap.RelocateApLoopFuncAddress,
 344     CpuMpData->AddressMap.RelocateApLoopFuncSize
 345     );
 346
 347   Status = gBS->CreateEvent (
 348                   EVT_TIMER | EVT_NOTIFY_SIGNAL,
 349                   TPL_NOTIFY,
 350                   CheckApsStatus,
 351                   NULL,
 352                   &mCheckAllApsEvent
 353                   );
 354   ASSERT_EFI_ERROR (Status);
 355
 356   //
 357   // Set timer to check all APs status.
 358   //
 359   Status = gBS->SetTimer (
 360                   mCheckAllApsEvent,
 361                   TimerPeriodic,
 362                   AP_CHECK_INTERVAL
 363                   );
 364   ASSERT_EFI_ERROR (Status);
 365
 366   Status = gBS->CreateEvent (
 367                   EVT_SIGNAL_EXIT_BOOT_SERVICES,
 368                   TPL_CALLBACK,
 369                   MpInitChangeApLoopCallback,
 370                   NULL,
 371                   &mMpInitExitBootServicesEvent
 372                   );
 373   ASSERT_EFI_ERROR (Status);
 374
 375   Status = gBS->CreateEventEx (
 376                   EVT_NOTIFY_SIGNAL,
 377                   TPL_CALLBACK,
 378                   MpInitChangeApLoopCallback,
 379                   NULL,
 380                   &gEfiEventLegacyBootGuid,
 381                   &mLegacyBootEvent
 382                   );
 383   ASSERT_EFI_ERROR (Status);
 384 }
 385
 386 /**
 387   This service executes a caller provided function on all enabled APs.
 388
 389   @param[in]  Procedure               A pointer to the function to be run on
 390                                       enabled APs of the system. See type
 391                                       EFI_AP_PROCEDURE.
 392   @param[in]  SingleThread            If TRUE, then all the enabled APs execute
 393                                       the function specified by Procedure one by
 394                                       one, in ascending order of processor handle
 395                                       number.  If FALSE, then all the enabled APs
 396                                       execute the function specified by Procedure
 397                                       simultaneously.
 398   @param[in]  WaitEvent               The event created by the caller with CreateEvent()
 399                                       service.  If it is NULL, then execute in
 400                                       blocking mode. BSP waits until all APs finish
 401                                       or TimeoutInMicroSeconds expires.  If it's
 402                                       not NULL, then execute in non-blocking mode.
 403                                       BSP requests the function specified by
 404                                       Procedure to be started on all the enabled
 405                                       APs, and go on executing immediately. If
 406                                       all return from Procedure, or TimeoutInMicroSeconds
 407                                       expires, this event is signaled. The BSP
 408                                       can use the CheckEvent() or WaitForEvent()
 409                                       services to check the state of event.  Type
 410                                       EFI_EVENT is defined in CreateEvent() in
 411                                       the Unified Extensible Firmware Interface
 412                                       Specification.
 413   @param[in]  TimeoutInMicrosecsond   Indicates the time limit in microseconds for
 414                                       APs to return from Procedure, either for
 415                                       blocking or non-blocking mode. Zero means
 416                                       infinity.  If the timeout expires before
 417                                       all APs return from Procedure, then Procedure
 418                                       on the failed APs is terminated. All enabled
 419                                       APs are available for next function assigned
 420                                       by MpInitLibStartupAllAPs() or
 421                                       MPInitLibStartupThisAP().
 422                                       If the timeout expires in blocking mode,
 423                                       BSP returns EFI_TIMEOUT.  If the timeout
 424                                       expires in non-blocking mode, WaitEvent
 425                                       is signaled with SignalEvent().
 426   @param[in]  ProcedureArgument       The parameter passed into Procedure for
 427                                       all APs.
 428   @param[out] FailedCpuList           If NULL, this parameter is ignored. Otherwise,
 429                                       if all APs finish successfully, then its
 430                                       content is set to NULL. If not all APs
 431                                       finish before timeout expires, then its
 432                                       content is set to address of the buffer
 433                                       holding handle numbers of the failed APs.
 434                                       The buffer is allocated by MP Initialization
 435                                       library, and it's the caller's responsibility to
 436                                       free the buffer with FreePool() service.
 437                                       In blocking mode, it is ready for consumption
 438                                       when the call returns. In non-blocking mode,
 439                                       it is ready when WaitEvent is signaled.  The
 440                                       list of failed CPU is terminated by
 441                                       END_OF_CPU_LIST.
 442
 443   @retval EFI_SUCCESS             In blocking mode, all APs have finished before
 444                                   the timeout expired.
 445   @retval EFI_SUCCESS             In non-blocking mode, function has been dispatched
 446                                   to all enabled APs.
 447   @retval EFI_UNSUPPORTED         A non-blocking mode request was made after the
 448                                   UEFI event EFI_EVENT_GROUP_READY_TO_BOOT was
 449                                   signaled.
 450   @retval EFI_UNSUPPORTED         WaitEvent is not NULL if non-blocking mode is not
 451                                   supported.
 452   @retval EFI_DEVICE_ERROR        Caller processor is AP.
 453   @retval EFI_NOT_STARTED         No enabled APs exist in the system.
 454   @retval EFI_NOT_READY           Any enabled APs are busy.
 455   @retval EFI_NOT_READY           MP Initialize Library is not initialized.
 456   @retval EFI_TIMEOUT             In blocking mode, the timeout expired before
 457                                   all enabled APs have finished.
 458   @retval EFI_INVALID_PARAMETER   Procedure is NULL.
 459
 460 **/
 461 EFI_STATUS
 462 EFIAPI
 463 MpInitLibStartupAllAPs (
 464   IN  EFI_AP_PROCEDURE          Procedure,
 465   IN  BOOLEAN                   SingleThread,
 466   IN  EFI_EVENT                 WaitEvent               OPTIONAL,
 467   IN  UINTN                     TimeoutInMicroseconds,
 468   IN  VOID                      *ProcedureArgument      OPTIONAL,
 469   OUT UINTN                     **FailedCpuList         OPTIONAL
 470   )
 471 {
 472   EFI_STATUS              Status;
 473
 474   //
 475   // Temporarily stop checkAllApsStatus for avoid resource dead-lock.
 476   //
 477   mStopCheckAllApsStatus = TRUE;
 478
 479   Status = StartupAllAPsWorker (
 480              Procedure,
 481              SingleThread,
 482              WaitEvent,
 483              TimeoutInMicroseconds,
 484              ProcedureArgument,
 485              FailedCpuList
 486              );
 487
 488   //
 489   // Start checkAllApsStatus
 490   //
 491   mStopCheckAllApsStatus = FALSE;
 492
 493   return Status;
 494 }
 495
 496 /**
 497   This service lets the caller get one enabled AP to execute a caller-provided
 498   function.
 499
 500   @param[in]  Procedure               A pointer to the function to be run on the
 501                                       designated AP of the system. See type
 502                                       EFI_AP_PROCEDURE.
 503   @param[in]  ProcessorNumber         The handle number of the AP. The range is
 504                                       from 0 to the total number of logical
 505                                       processors minus 1. The total number of
 506                                       logical processors can be retrieved by
 507                                       MpInitLibGetNumberOfProcessors().
 508   @param[in]  WaitEvent               The event created by the caller with CreateEvent()
 509                                       service.  If it is NULL, then execute in
 510                                       blocking mode. BSP waits until this AP finish
 511                                       or TimeoutInMicroSeconds expires.  If it's
 512                                       not NULL, then execute in non-blocking mode.
 513                                       BSP requests the function specified by
 514                                       Procedure to be started on this AP,
 515                                       and go on executing immediately. If this AP
 516                                       return from Procedure or TimeoutInMicroSeconds
 517                                       expires, this event is signaled. The BSP
 518                                       can use the CheckEvent() or WaitForEvent()
 519                                       services to check the state of event.  Type
 520                                       EFI_EVENT is defined in CreateEvent() in
 521                                       the Unified Extensible Firmware Interface
 522                                       Specification.
 523   @param[in]  TimeoutInMicrosecsond   Indicates the time limit in microseconds for
 524                                       this AP to finish this Procedure, either for
 525                                       blocking or non-blocking mode. Zero means
 526                                       infinity.  If the timeout expires before
 527                                       this AP returns from Procedure, then Procedure
 528                                       on the AP is terminated. The
 529                                       AP is available for next function assigned
 530                                       by MpInitLibStartupAllAPs() or
 531                                       MpInitLibStartupThisAP().
 532                                       If the timeout expires in blocking mode,
 533                                       BSP returns EFI_TIMEOUT.  If the timeout
 534                                       expires in non-blocking mode, WaitEvent
 535                                       is signaled with SignalEvent().
 536   @param[in]  ProcedureArgument       The parameter passed into Procedure on the
 537                                       specified AP.
 538   @param[out] Finished                If NULL, this parameter is ignored.  In
 539                                       blocking mode, this parameter is ignored.
 540                                       In non-blocking mode, if AP returns from
 541                                       Procedure before the timeout expires, its
 542                                       content is set to TRUE. Otherwise, the
 543                                       value is set to FALSE. The caller can
 544                                       determine if the AP returned from Procedure
 545                                       by evaluating this value.
 546
 547   @retval EFI_SUCCESS             In blocking mode, specified AP finished before
 548                                   the timeout expires.
 549   @retval EFI_SUCCESS             In non-blocking mode, the function has been
 550                                   dispatched to specified AP.
 551   @retval EFI_UNSUPPORTED         A non-blocking mode request was made after the
 552                                   UEFI event EFI_EVENT_GROUP_READY_TO_BOOT was
 553                                   signaled.
 554   @retval EFI_UNSUPPORTED         WaitEvent is not NULL if non-blocking mode is not
 555                                   supported.
 556   @retval EFI_DEVICE_ERROR        The calling processor is an AP.
 557   @retval EFI_TIMEOUT             In blocking mode, the timeout expired before
 558                                   the specified AP has finished.
 559   @retval EFI_NOT_READY           The specified AP is busy.
 560   @retval EFI_NOT_READY           MP Initialize Library is not initialized.
 561   @retval EFI_NOT_FOUND           The processor with the handle specified by
 562                                   ProcessorNumber does not exist.
 563   @retval EFI_INVALID_PARAMETER   ProcessorNumber specifies the BSP or disabled AP.
 564   @retval EFI_INVALID_PARAMETER   Procedure is NULL.
 565
 566 **/
 567 EFI_STATUS
 568 EFIAPI
 569 MpInitLibStartupThisAP (
 570   IN  EFI_AP_PROCEDURE          Procedure,
 571   IN  UINTN                     ProcessorNumber,
 572   IN  EFI_EVENT                 WaitEvent               OPTIONAL,
 573   IN  UINTN                     TimeoutInMicroseconds,
 574   IN  VOID                      *ProcedureArgument      OPTIONAL,
 575   OUT BOOLEAN                   *Finished               OPTIONAL
 576   )
 577 {
 578   EFI_STATUS              Status;
 579
 580   //
 581   // temporarily stop checkAllApsStatus for avoid resource dead-lock.
 582   //
 583   mStopCheckAllApsStatus = TRUE;
 584
 585   Status = StartupThisAPWorker (
 586              Procedure,
 587              ProcessorNumber,
 588              WaitEvent,
 589              TimeoutInMicroseconds,
 590              ProcedureArgument,
 591              Finished
 592              );
 593
 594   mStopCheckAllApsStatus = FALSE;
 595
 596   return Status;
 597 }
 598
 599 /**
 600   This service switches the requested AP to be the BSP from that point onward.
 601   This service changes the BSP for all purposes. This call can only be performed
 602   by the current BSP.
 603
 604   @param[in] ProcessorNumber   The handle number of AP that is to become the new
 605                                BSP. The range is from 0 to the total number of
 606                                logical processors minus 1. The total number of
 607                                logical processors can be retrieved by
 608                                MpInitLibGetNumberOfProcessors().
 609   @param[in] EnableOldBSP      If TRUE, then the old BSP will be listed as an
 610                                enabled AP. Otherwise, it will be disabled.
 611
 612   @retval EFI_SUCCESS             BSP successfully switched.
 613   @retval EFI_UNSUPPORTED         Switching the BSP cannot be completed prior to
 614                                   this service returning.
 615   @retval EFI_UNSUPPORTED         Switching the BSP is not supported.
 616   @retval EFI_DEVICE_ERROR        The calling processor is an AP.
 617   @retval EFI_NOT_FOUND           The processor with the handle specified by
 618                                   ProcessorNumber does not exist.
 619   @retval EFI_INVALID_PARAMETER   ProcessorNumber specifies the current BSP or
 620                                   a disabled AP.
 621   @retval EFI_NOT_READY           The specified AP is busy.
 622   @retval EFI_NOT_READY           MP Initialize Library is not initialized.
 623
 624 **/
 625 EFI_STATUS
 626 EFIAPI
 627 MpInitLibSwitchBSP (
 628   IN UINTN                     ProcessorNumber,
 629   IN BOOLEAN                   EnableOldBSP
 630   )
 631 {
 632   EFI_STATUS            Status;
 633   BOOLEAN               OldInterruptState;
 634
 635   //
 636   // Before send both BSP and AP to a procedure to exchange their roles,
 637   // interrupt must be disabled. This is because during the exchange role
 638   // process, 2 CPU may use 1 stack. If interrupt happens, the stack will
 639   // be corrupted, since interrupt return address will be pushed to stack
 640   // by hardware.
 641   //
 642   OldInterruptState = SaveAndDisableInterrupts ();
 643
 644   //
 645   // Mask LINT0 & LINT1 for the old BSP
 646   //
 647   DisableLvtInterrupts ();
 648
 649   Status = SwitchBSPWorker (ProcessorNumber, EnableOldBSP);
 650
 651   //
 652   // Restore interrupt state.
 653   //
 654   SetInterruptState (OldInterruptState);
 655
 656   return Status;
 657 }
 658
 659 /**
 660   This service lets the caller enable or disable an AP from this point onward.
 661   This service may only be called from the BSP.
 662
 663   @param[in] ProcessorNumber   The handle number of AP.
 664                                The range is from 0 to the total number of
 665                                logical processors minus 1. The total number of
 666                                logical processors can be retrieved by
 667                                MpInitLibGetNumberOfProcessors().
 668   @param[in] EnableAP          Specifies the new state for the processor for
 669                                enabled, FALSE for disabled.
 670   @param[in] HealthFlag        If not NULL, a pointer to a value that specifies
 671                                the new health status of the AP. This flag
 672                                corresponds to StatusFlag defined in
 673                                EFI_MP_SERVICES_PROTOCOL.GetProcessorInfo(). Only
 674                                the PROCESSOR_HEALTH_STATUS_BIT is used. All other
 675                                bits are ignored.  If it is NULL, this parameter
 676                                is ignored.
 677
 678   @retval EFI_SUCCESS             The specified AP was enabled or disabled successfully.
 679   @retval EFI_UNSUPPORTED         Enabling or disabling an AP cannot be completed
 680                                   prior to this service returning.
 681   @retval EFI_UNSUPPORTED         Enabling or disabling an AP is not supported.
 682   @retval EFI_DEVICE_ERROR        The calling processor is an AP.
 683   @retval EFI_NOT_FOUND           Processor with the handle specified by ProcessorNumber
 684                                   does not exist.
 685   @retval EFI_INVALID_PARAMETER   ProcessorNumber specifies the BSP.
 686   @retval EFI_NOT_READY           MP Initialize Library is not initialized.
 687
 688 **/
 689 EFI_STATUS
 690 EFIAPI
 691 MpInitLibEnableDisableAP (
 692   IN  UINTN                     ProcessorNumber,
 693   IN  BOOLEAN                   EnableAP,
 694   IN  UINT32                    *HealthFlag OPTIONAL
 695   )
 696 {
 697   EFI_STATUS     Status;
 698   BOOLEAN        TempStopCheckState;
 699
 700   TempStopCheckState = FALSE;
 701   //
 702   // temporarily stop checkAllAPsStatus for initialize parameters.
 703   //
 704   if (!mStopCheckAllApsStatus) {
 705     mStopCheckAllApsStatus = TRUE;
 706     TempStopCheckState     = TRUE;
 707   }
 708
 709   Status = EnableDisableApWorker (ProcessorNumber, EnableAP, HealthFlag);
 710
 711   if (TempStopCheckState) {
 712     mStopCheckAllApsStatus = FALSE;
 713   }
 714
 715   return Status;
 716 }